@article{TM_2009_266_a8, author = {S. A. Melikhov}, title = {The van {Kampen} {Obstruction} and {Its} {Relatives}}, journal = {Trudy Matematicheskogo Instituta imeni V.A. Steklova}, pages = {149--183}, publisher = {mathdoc}, volume = {266}, year = {2009}, language = {en}, url = {http://geodesic.mathdoc.fr/item/TM_2009_266_a8/} }